I am currently building a 4* 40, and at the point of mounting the engine mount on the planes it gives the center line, and a thrust line. my question is what part of engine sits on the thrust line. I am new at this so I have no idea, so if someone out there knows anything about this please let me know, any and all info is greatly appreciated. thanks in advance for the help. carver-in-sc

The prop shaft should match the thrust line. With my OS, the top of the mount rails match the thrust line and the engine is mounted to the top of the rails. I suspect that is true of most engines.

Scott

scott thank you very much for the info greatly appriciated, on the thrust line info again thanks. frank (carver-in-sc)

Hi Carver--I've built the 4* 40 and a couple of 60's. The fire wall is installed with the correct thrust angle. Just use the template that comes with the kit to lay out the motor mount. The kit comes with Sig's 2 piece motor mount. I like to temporarily install engine to mount beams using small sheet metal screws, then attach to fire wall to get the holes correct. Then you can slide the engine in/out as requried for proper CG and looks. As I recall, you can move the engine around about an inch. Makes a big difference in CG and may prevent adding useless weight.

Good luck-let us know how it flies.

Greg

Ditto

Hey Carver, ever think of installing the engine 90 degrees with the muffler down? Believe this change would streamline the fuse top, and give it a more striking appearance. I started my kit a while back, and got distracted from completing it. Decided on the 90 degree engine mounting, and some fuse bashing to make it look like a WWII Fighter. Still plan to do this once the new hobby room is completed in October. Get back to me what you think about my changes.

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hi everyone, aerorich like the idea of rotating the engine 90 degrees,have to give it a try before completely mounting eng. to see what it looks like. and flying greg, I like your idea of using the sheet metal screws to hold engine will try this one also everyone you have all been a great help to me and I will more than likely be back on with more ques. certainly with completed pics again thanks frank(carver-in-sc).

Aerotich--I 've seen a few 4* of various sizes that have been modified to resemble different aircraft. That's the great thing about this hobby--experimentation and adaptation. Some guys have made cowls. I have left my engines upright, just for ease of operation and have always gone with 4 strokes (except the brief time I had a Super Tiger .61 with a pipe on my 60 sized 4*. My OS 91FS was on another plane and I just had to fly the 4*). I had skis on my 40 sized for a while--it was a blast in snow.

There are probably threads on bashed 4* if you look in Sport, Beginner or Kit Building forums.

Greg

It is the bottom of the mounting flanges on the engine that are centered on the thrust line. So the top rails on the engine MOUNT should be centered

A picture is worth a thousand words!